boy, it's nice to be needed. He probably wants to make sure you do this as a "together" activity, which is flattering, right?
Have you tried coaching him through it? actually making his fingers do the work while you stand behind him? it may take some coaxing, but with a "you can do this" attitude, I bet he will learn, just like he did with cutting and piecing.
keep up the good work!! Can you post pics of his tops?